US8689430B1 - Method for providing a perpendicular magnetic recording (PMR)head - Google Patents

Abstract

A method and system for providing a perpendicular magnetic recording (PMR) head are disclosed. A PMR pole having a bottom and a top wider than the bottom is provided. The PMR pole may be formed by depositing a PMR pole layer, then removing part of the PMR pole layer, leaving the PMR pole. The PMR pole may also be provided by forming a trench having the desired profile in a photoresist layer, depositing the PMR pole layer, then removing the photoresist layer, leaving the PMR pole in the location of the trench. A side gap is deposited over the PMR pole. A side shield is provided on the side gap. A planarization that removes part of the side shield on the PMR pole is performed. A top gap is provided on the PMR pole, substantially covering the entire PMR pole. A top shield is provided on the top gap.

Description

FIELD OF THE INVENTION

The present invention relates to magnetic recording technology, and more particularly to a method and system for providing perpendicular magnetic recording heads having wrap around shields.

BACKGROUND

Conventional perpendicular magnetic recording (PMR) heads may be unshielded or shielded. Although easier to fabricate and having higher write fields, unshielded heads have a low gradient field. Such a low gradient field results in less sharp transitions and lower signal to noise ratios, which are undesirable. Consequently, shielding is typically provided in conventional PMR heads.

FIG. 1 depicts a portion of aconventional PMR head10, as viewed from the air-bearing surface (ABS). Theconventional PMR head10 is a shielded head. Theconventional PMR head10 is typically part of a merged head including thePMR head10 and a read head (not shown) and typically resides on a slider (not shown). For clarity, theconventional PMR head10 is not drawn to scale.

Theconventional PMR head10 includes a conventionalfirst pole12,alumina insulating layer14,alumina underlayer16 that may be considered part of thealumina insulating layer14, aconventional PMR pole18 that typically includes a seed layer (not shown),insulating layer20,shield gap26, andtop shield28. Note that in certain other embodiments, thetop shield28 may also act as pole during writing using theconventional PMR head10. Theconventional PMR pole18 is surrounded byinsulating layer20. Similarly, thetop shield28 is surrounded by another insulating layer (not shown). Theconventional PMR pole18 hassidewalls22 and24. In conventional applications, the height of theconventional PMR pole18 is typically less than approximately three-tenths micrometer. Theconventional PMR pole18 also has a negative angle such that the top of theconventional PMR pole18 is wider than the bottom of theconventional PMR pole18. Stated differently, the angle θ of the sidewalls is less than ninety degrees in theconventional PMR pole18 ofFIG. 1. A pole having this height and shape is desirable for use in PMR applications.

Because theconventional PMR head10 utilizes atop shield28, the gradient field is improved. In addition, the net magnetic field from theconventional PMR head10 is at an angle to the perpendicular direction. However, performance of theconventional PMR head10 may still suffer due to stray side fields. Such stray side fields may cause side erasure of adjacent tracks. In addition, such a wider field profile may give rise to increased magnetic track width. Consequently, the reduced track pitch required for ultrahigh density recording may not be achieved.

FIG. 2 depicts a portion of aconventional PMR head10′, as viewed from the air-bearing surface (ABS). Theconventional PMR head10′ is a shielded head that includes side shields. Theconventional PMR head10′ is typically part of a merged head including thePMR head10 and a read head (not shown) and typically resides on a slider (not shown). For clarity, theconventional PMR head10′ is not drawn to scale.

Theconventional PMR head10′ includes components that are analogous to those in theconventional PMR head10. Such components are labeled similarly. Thus, theconventional PMR head10′ includes a conventionalfirst pole12′,alumina insulating layer14′,alumina underlayer16′ that may be considered part of thealumina insulating layer14′, aconventional PMR pole18′ that typically includes a seed layer (not shown),shield gap26′, andshield28′. Theshield28′ includestop shield28A andside shield28B portions. Similarly, theshield gap26′ includestop gap26A andside gap26B portions.

FIG. 3 is a flow chart depicting aconventional method50 for fabricating the conventional PMR head having a side shield. For simplicity, some steps are omitted. Theconventional method50 is described in the context of theconventional PMR head10′. Theconventional method50 starts during formation of thePMR pole18′. ThePMR pole18′ is defined, viastep52. Theshield gap26′ is deposited, viastep54. Thus, both thetop gap26A and theside gap26B are deposited instep54. A photoresist mask (not shown) for theshield28′ is provided, viastep56. Theshield28′ is plated, viastep58. The photoresist mask used for theshield28′ is then removed, viastep60. Fabrication of thePMR head10′ is then completed, viastep62. Thus, thePMR head10′ may be formed.

Although theconventional method50 may be used to fabricate theconventional PMR head10′, there are significant drawbacks. For example, the throat height (length perpendicular to the ABS) of thetop shield portion28A and theside shield portion28B are the same. Similarly, the thicknesses of the topshield gap portion26A and the sideshield gap portions26B are the same. This may adversely affect performance of theconventional PMR head10′. In addition, the photolithography carried out for forming the resist masks instep56 takes place on thepole18′. As a result, the thickness of the mask may be uneven. Poor edge definition and location may thus result.

Accordingly, what is needed is an improved method for fabricating a PMR head.

SUMMARY

A method and system for providing a perpendicular magnetic recording head are disclosed. The method and system include forming a perpendicular magnetic recording pole having a bottom and a top wider than the bottom. The method and system also include depositing a side gap over the PMR pole and providing a side shield on the side gap. The method and system also include performing a planarization step that removes a portion of the side shield on the PMR pole. The method and system also include providing a top gap on the PMR pole. The top gap covers substantially only the PMR pole. The method and system further include providing a top shield.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is diagram depicting a conventional PMR head.

FIG. 2 is diagram depicting another conventional PMR head.

FIG. 3 is a flow chart depicting a conventional method for fabricating a PMR head having side shields.

FIG. 4 is a flow chart depicting one embodiment of a method for fabricating a PMR head.

FIGS. 5A-5E are diagrams depicting the ABS views of an exemplary embodiment of a perpendicular magnetic recording head during fabrication.

FIG. 6 is a diagram depicting the ABS views of another exemplary embodiment of a perpendicular magnetic recording head during fabrication.

FIG. 7 is a diagram depicting the ABS views of another exemplary embodiment of a perpendicular magnetic recording head during fabrication.

FIG. 8 is a diagram depicting the ABS views of another exemplary embodiment of a perpendicular magnetic recording head during fabrication.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4 is a flow chart depicting one embodiment of amethod100 for fabricating a PMR head.FIGS. 5A-5E are diagrams depicting the ABS views of an exemplary embodiment of aPMR head200 during fabrication. Referring toFIGS. 4-5E, themethod100 is described in the context of thePMR head200. For simplicity, some steps may be omitted. In addition, for clarity, thePMR head200 is not drawn to scale. ThePMR head200 is preferably part of a merged head that also includes a read head (not shown) and resides on a slider (not shown). Themethod100 also preferably commences after formation of a first pole and formation of layers that will reside under a second pole. For clarity, thePMR head200 is not drawn to scale.

A PMR pole is formed, viastep102. In a preferred embodiment, the pole is formed using one of two processes. One process used is termed a pseudo-damascene process. In such a process, step102 preferably includes depositing a layer of photoresist, providing a trench having a desired shape for the PMR pole in the photoresist, depositing the PMR pole in the trench, and removing the photoresist. The other such process is termed a mill-and-lap process. In the mill-and-lap process, material for the PMR pole is plated, a mask that covers the PMR pole is formed, and the PMR pole is defined (or trimmed) using the mask, preferably using an ion mill. In forming the PMR pole in either the pseudo damascene or the mill-and-lap process, multiple layers may be provided. For example seed and/or glue layers may be provided below the PMR pole. In the mill-and-lap process, a planarization stop layer may be provided on the PMR pole layer. In the pseudo-damascene process, a planarization stop layer is preferably not used. Instead, support structures spaced apart from the PMR pole may be used during a planarization. In addition, the PMR pole may be formed instep102 on a metal underlayer, directly on an insulator, or on another layer. The PMR pole may be sputter deposited or electroplated using high moment materials.FIG. 5A depicts one embodiment of aPMR head200 afterstep102 is performed. ThePMR head200 includes aninsulator201 that preferably resides on a first pole (not shown). In the embodiment shown, ametal underlayer202 is used. ThePMR pole204 is also depicted. ThePMR pole204 is preferably trapezoidal in shape, having a top that is wider than the bottom.Multiple layers206 may also have been provided on thePMR pole204. However, in another embodiment, thelayers206 may not be used.

A side gap is deposited on thePMR pole204, viastep104. Examples of processes used for depositing the side gap may include physical vapor deposition, collimated physical vapor deposition, ion beam deposition, atomic layer deposition, and chemical vapor deposition. In a preferred embodiment, the side gap is blanket deposited on thePMR head100. Also in a preferred embodiment, atomic layer deposition is used instep104. The side gap is preferably at least five hundred Angstroms thick and no more than two thousand Angstroms thick. The thickness of the side gap deposited instep104 may be selected based on the design requirements of thePMR head200.FIG. 5B depicts thePMR head200 after deposition of theside gap208. Theside gap208 may be insulating. In a preferred embodiment, theside gap208 includes at least one of aluminum oxide, silicon oxide, silicon nitride, and tantalum oxide. Depending upon the process used, the thickness of theside gap208 on the side walls of thePMR pole204 may be different than the thickness on the top (horizontal portion) of thePMR pole204. For example, physical vapor deposition and collimated physical vapor deposition may result in aside gap208 that is thinner on the sidewalls than on the top of thePMR pole204. Ion beam deposition, atomic layer deposition, and chemical vapor deposition may result in aside gap208 that has almost the same thickness on the top of thePMR pole204 as the sidewalls of thePMR pole204. In addition, if other deposition techniques are used, theside gap208 may have a different shape. For example, if conformal deposition techniques, such as atomic layer deposition, are used, the side gap may conform to shape of thePMR pole204. In such an embodiment, the side walls of the side gap may have a negative angle similar to θ.

A side shield is deposited on the PMR head, viastep106. Step106 may also include depositing seed layers for the side shield and forming a mask having an aperture in the region of thePMR pole204. In a preferred embodiment, the side shield is plated. However, in another embodiment, another deposition method may be used.FIG. 5C depicts thePMR head200 afterstep106 is performed. Thus, theside shield210 is shown. The layer for theside shield210 encapsulates thePMR pole204.

A planarization is performed, viastep108. In a preferred embodiment, a chemical mechanical planarization (CMP) is used. The planarization step removes a portion of theside shield210 and exposes the stack for thePMR pole204. In addition, the top portion of theside gap208 is removed.FIG. 5D depicts thePMR head200 afterstep108 has been performed. Thus, side shields210A and210B remain. In addition, the stack including thePMR pole204 has been exposed. A portion of theside gaps208A and208B are also exposed. In the embodiment shown, a portion of the top layer(s)206 has been removed, leaving thelayers206′. In another embodiment, thelayers206′ may be completely removed. A substantially flat surface211 is also provided by the planarization.

A top gap is provided on the PMR pole, viastep110. The top gap may be formed of the same material as theside gaps210A and210B or may be formed of another material. In some embodiments,step110 is performed when thePMR pole204 is formed. In such an embodiment, the top gap may be formed under the planarization layer described above with respect to the mill-and-lap process. However, in another embodiment, thetop gap110 may be formed at a different time than thePMR pole204. The top shield is provided, viastep112. The top shield is preferably formed by plating the shield. In addition, a seed layer and an etch to remove a portion of the top shield may be performed instep112. However, another deposition method could be used. Fabrication of thePMR head200 may then be completed, via step114.FIG. 5E depicts thePMR head200 afterstep112 has been performed. Thus, thetop gap212 and thetop shield214 have been provided. In the embodiment shown, thetop gap212 covers substantially only thePMR pole204. In the embodiment shown inFIG. 5E, the thickness, t, of thetop gap212 is different from the width, w, of theside gaps208A and208B. In one embodiment, the width, w, is at least twice the thickness, t. For example, in one embodiment, theside gaps208A and208B may be more than one hundred nanometers, while thetop shield gap212 may be fifty nanometers or less. In another embodiment, the width, w, is at least three times the thickness, t.

Thus, themethod100 may be used to provide thePMR head200. Because they are formed separately, thetop gap212 and theside gaps208A and208B can be configured independently. Thus, the width ofside gaps208A and208B can differ from the thickness of thetop gap212. More particularly, the width of theside gaps208A and208B may, for example, be two to three times the thickness of thetop gap212. Consequently, better magnetic performance can be achieved. In addition, because the planarization performed instep108 results in a flat topology, thetop shield212 is provided on a relatively flat topology. Consequently, better edge definition and edge location control may be provided. In addition, the side shields210A and210B and thetop shield214 may be configured independently. As a result, the throat height (perpendicular to the page inFIGS. 5A-5E) of thetop shield214 may be set independently from the throat height of the side shields210A and210B. For example, the throat height of thetop shield214 may be set to 0.2 μm or less, while the throat height of the side shields210A and210B may be larger. Consequently, the desired field strength, gradient, and angle may be achieved while providing side shields for reducing inadvertent side erasure of adjacent tracks. Consequently, a reduced track pitch for ultrahigh density recording may be achieved. Furthermore, themethod100 may be relatively easily incorporated into existing methods for fabricating PMR heads. Thus, the benefits of thePMR head200 may be achieved without radically altering existing fabrication methods.

FIG. 6 is a diagram depicting the ABS views of another exemplary embodiment of aPMR head200′ during fabrication. In addition, for clarity, thePMR head200′ is not drawn to scale. ThePMR head200′ is preferably formed using themethod100. In addition, thePMR head200′ is analogous to thePMR head200 and, therefore, has components that are labeled similarly. ThePMR head200′ thus includes aPMR pole204′ that may be formed on ametal underlayer202′ andunderlying insulator201′,side gaps208A′ and208B′, side shields210A′ and210B′,top gap212′ andtop shield214′. ThePMR head200′ may also includeadditional layers206′.

Thetop gap212′ in thePMR head200′ is fabricated instep110 of themethod100. However, for thePMR head200′, thetop gap212′ is configured to separate thetop shield214′ from the side shields210A′ and210B′. However, for thePMR head200′, theside gaps208A′ and208B′ can still be configured separately from thetop gap212′. Similarly, the side shields210A′ and210B′ may be configured separately. In addition, the topology of thePMR head200′ after formation of thetop gap212′ and in preparation for providing thetop shield214′ is quite flat. Consequently, the benefits of thePMR head200 may also be achieved for thePMR head200′.

FIG. 7 is a diagram depicting the ABS views of another exemplary embodiment of aPMR head200″ during fabrication. In addition, for clarity, thePMR head200″ is not drawn to scale. ThePMR head200″ is preferably formed using themethod100. In addition, thePMR head200″ is analogous to thePMR head200 and, therefore, has components that are labeled similarly. ThePMR head200″ thus includes aPMR pole204″ that may be formed on ametal underlayer202″ andunderlying insulator201″,side gaps208A″ and208B″, side shields210A″ and210B″,top gap212″ andtop shield214″. ThePMR head200″ may also includeadditional layers206″.

Thetop gap212″ in thePMR head200″ is fabricated instep110 of themethod100. However, for thePMR head200″, thetop gap212″ is configured extend over theside gaps208A″ and208B″ without separating thetop shield214″ from the side shields210A″ and210B″. For thePMR head200″, theside gaps208A″ and208B″ can still be configured separately from thetop gap212″. Similarly, the side shields210A″ and210B″ may be configured separately. In addition, the topology of thePMR head200″ after formation of thetop gap212″ and in preparation for providing thetop shield214″ is quite flat. Consequently, the benefits of the PMR heads200 and200′ may also be achieved for thePMR head200″.

FIG. 8 is a diagram depicting the ABS views of another exemplary embodiment of aPMR head200′″ during fabrication. For clarity, thePMR head200′″ is not drawn to scale. ThePMR head200′″ is preferably formed using themethod100. In addition, thePMR head200′″ is analogous to thePMR head200 and, therefore, has components that are labeled similarly. ThePMR head200′″ thus includes aPMR pole204′″ that may be formed on ametal underlayer202′″ andunderlying insulator201′″,side gaps208A′″ and208B′″, side shields210A′″ and210B′″,top gap212′″ andtop shield214′″. ThePMR head200′″ may also includeadditional layers206′″.

Theside gaps208A′″ and208B′″ in thePMR head200′″ are deposited instep104 of themethod100. For thePMR head200′″, a conformal deposition technique, such as atomic layer deposition, is used instep104. Consequently, the sidewalls of theside gaps208A′″ and208B′″ have a negative angle that is similar to that of thePMR pole204′″. Theside gaps208A′″ and208B′″ can still be configured separately from thetop gap212′″. Similarly, the side shields210A′″ and210B′″ may be configured separately. In addition, the topology of thePMR head200′″ after formation of thetop gap212′″ and in preparation for providing thetop shield214′″ is quite flat. Consequently, the benefits of the PMR heads200,200′, and200″ may also be achieved for thePMR head200′″.

Thus, using themethod100, fabrication, performance, and reliability ofPMR transducers200,200′,200″, and200′″ may be improved.

Claims (12)

We claim:

1. A method for providing a perpendicular magnetic recording (PMR) head comprising:

forming a PMR pole having a bottom and a top wider than the bottom, the step of forming the PMR pole further including

providing a resist layer;

forming a trench in the resist layer, the trench having a trench bottom and a trench top wider than the trench bottom; and

plating the at least one magnetic pole layer, a portion of the at least one magnetic pole layer residing in the trench;

depositing a side gap over the PMR pole;

providing a side shield on the side gap;

performing a planarization step, the planarization step removing a portion of the side shield on the PMR pole;

providing a top gap on the PMR pole, the top gap covering substantially at least the PMR pole; and

providing a top shield.

2. The method ofclaim 1 wherein the pole forming further includes:

providing a metal underlayer, the PMR pole layer residing on the metal underlayer.

3. The method ofclaim 2 wherein the pole forming further includes:

forming a mask on the at least one magnetic pole layer;

defining the PMR pole utilizing the mask.

4. The method ofclaim 1 wherein the pole forming further includes:

providing a planarization stop layer on the at least one magnetic pole layer.

5. The method ofclaim 4 wherein the planarization stop layer is a diamond-like carbon layer and wherein the pole forming further includes:

performing a chemical mechanical planarization on the at least one magnetic pole layer.

6. The method ofclaim 4 wherein the pole forming further comprising:

removing a remaining portion of the planarization stop layer before the top gap is formed.

7. The method ofclaim 1 wherein the top gap has a thickness and the side gap has a width, a ratio of the width to the thickness being greater than one.

8. The method ofclaim 7 wherein the ratio of the width to the thickness is at least two.

9. The method ofclaim 7 wherein the ratio of the width to the thickness is at least three.

10. The method ofclaim 1 wherein the side gap includes:

providing at least one of an aluminum oxide layer, a silicon oxide layer, a silicon nitride layer, and a tantalum oxide layer.

11. A method for providing a perpendicular magnetic recording (PMR) head comprising:

forming a PMR pole having a bottom and a top wider than the bottom;

depositing a side gap over the PMR pole;

providing a side shield on the side gap;

performing a planarization step, the planarization step removing a portion of the side shield on the PMR pole;

providing a top gap on the PMR pole, the top gap covering substantially at least the PMR pole; and

providing a top shield;

wherein the step of providing the pole further includes;

providing a metal underlayer;

providing a resist layer;

forming a trench in the resist layer, the trench having a trench bottom and a trench top wider than the trench bottom; and

plating the at least one magnetic pole layer, a portion of the at least one magnetic pole layer residing in the trench.

12. A method for providing a perpendicular magnetic recording (PMR) head comprising:

forming a PMR pole having a bottom and a top wider than the bottom, the PMR pole forming including forming the PMR pole utilizing a pseudo-damascene process;

depositing a side gap over the PMR pole, the side gap having a width;

providing a side shield on the side gap;

performing a planarization step, the planarization step removing a portion of the side shield on the PMR pole;

providing a top gap on the PMR pole, the top gap covering the PMR pole, the top gap having a thickness, a ratio of the width of the side gap to the thickness of the top gap being at least two; and

providing a top shield.

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